Elastic fabric and process of making same



'March 12, 1946.

s. w. ALDERFER 2,396,483

ELASTIC FABRIC AND PROCESS OF MAKING SAME (DUAL ELASTIC) Filed May 22,1944 INVENTOR STEQLING \MALPERFER ATTORNEYS Patented Mar. 12, 1946ELASTIC FABRIC AND PROCESS OF MAKING SAME (DUAL ELASTIC) Sterling W.Alderfer, Akron, Ohio, asslgnor of one-half to Edward D. Andrews, Akron,Ohio -Application May 22, 1944, Serial No. 536,831

15 Claims.

The present invention relates to a new and improved elastic fabric inwhich threads or strands of rubber or other elastic material arecombined with cotton, rayon or other textile material. In the usual typeof elastic fabrics a plurality of rubber threads, each covered by awinding or plurality of windings of textile material are woven orknitted into a fabric. These methods require at least two operations,one the covering of the elastic core and the othe the fabrication of thecomplete fabric structure.

The present invention is for an improvement in the methods heretoforeemployed in the manufacture of commercial elastic fabrics in that thecovering of the elastic cores and the weaving of the fabric are done ina single operation. This is accomplished by wrapping the outer coveringelements about the several elastic cores to form a series of parallelcables which are to constitute the warp'threads or elements 'of thecompleted fabric and concurrently with the formation of cables, passinga weft or pick thread through the cables to form the completed fabric ina single operation. In these respects the method partakes of the methodshown and described in my prior copending application, Serial No.534,631 filed May 8, 1944.

In the former application referred to each cable is composed of a singleelastic thread or core and a plurality of covering strands which arewrapped around the core, this result being due to the fact that theelastic core is maintained under a considerable tension during the cableforming operation. In the present application, however, each elasticcore is composed of a plurality of elastic threads which are twistedtogether under tension to form a cable, the covering strands wrappingthemselves about the central cable.

One advantage of any fabric made in accordance with the presentinvention is that in the event either of the elastic threadsconstituting the core should be broken, it Will be held more firmly eventhan in the fabric made by the method of the prior application referredto. An.

objection to the ordinary types of elastic fabric which preceded myimprovements referred to, is that when an elastic thread, which isalways under tension, is broken. it will etract-on either side of thebreak and the elasticity of the fab ric or webbing is thereby impaired.In a fabric made in accordance with the present invention each of theelastic threads or filaments which constitute a single elastic core isgripped not only by the pick thread which is woven through the cable,but each elastic filament is wrapped about its companion filament sothat it grips and holds the other filament. As a consequence, if one ofthe filaments breaks, it is effectively held by its companion filament,as wellas by the presence of the embedded pick thread. It very rarelyoccurs that both filaments of the core will break at the same point;therefore at any point where a single filament is'broken, its ends willbe interlocked and gripped by the other filament of the core and'thetendency of the broken filament to retract from the point of the breakwill be greatly reduced. Another advantage of the present invention overthe prior art and over that shown'in my prior application is that theelastic core is in the nature of a dual filament, that is to say, it ismade up of at least two filament which are more or less independent ofone another. The most frequent cause of failure of an elastic core isthat it is nicked by the needles used in manufac turing garments orother articles of apparel. In the fabric illustrated herein it isextremely unlikely that a needle will nick both filaments at the samepoint. This mean that only one filament will break due to such a causeand the re-' maining filament will be unaffected and will continue tofunction.

The fabric has the additional advantage over all other types of elasticfabric in that even if both elastic filaments should break at the samepoint, the filaments, being twisted together, will tend to knot, due tothe fact that they must rotate to retract. Any knot thus formed Will beintercepted by an adjacent pick which lies between the two filaments andfurther retraction of the filaments will be halted.

Other objects and advantages are achieved by practicing the invention asillustrated and described herein. In the drawing the new method ofmanufacturing elastic fabrics or webbing and the new product producedthereby are shown with sufiicient detail to enable those familiar withthe art to practice the invention. It will be understood, however, thatthe showing is merely illustrative and that variations and modificationsmay readily be conceived that would not alter the basic principles ofthe invention.

In the drawing:

Figs. 1 and 2 are, respectively, a side elevation and a plan view of thebasic elements required for making the new type of elastic fabric by themethod of the invention. In these views six cables are shown asconstituting the finished fabric or webbing, but it will be understoodthat the I I number of {cables constituting the warp threads of thefabric may be increased or diminished to any desired extent. In theseviews also the cabletwists are arranged so that the cables are groupedthree and three, i. e. with three right hand and three left hand twists.It is desirable to balance the twists more or less equally in theseveral cables which make up the warp threads and the method illustratedis onemeans of securing this result. Also the pattern of the finishedfabric is determined by the direction of cable-twists.

Fig. 3 isa plan view of another type of fabric made by the use of theinvention, this view illustrating a six cable fabric or webbing in whichthe twists in the cables are alternated.

Fig. 4 is an'edge view of the fabric shown in Fig. 3. I 4

Fig. 5 is asection on the line I5 of Fig. 3.

When the invention has been disclosed it is possible to devise manyvariations and modifications and to secure a great variety of patternswhich it would be impractical to detail completely. The

' illustrations given in the drawing and in the specification are merelyexplanatory and not to be construed as confining or limiting theinvention to those forms.

The method consists of providing a plurality of closely arrangedparallel disks or cards" equal to the number of cables which are to bewoven as warp threads of the complete fabric or w bbing. Each of thesedisks is provided with a plurality of holes through which the elasticthreads and the desired number of textile covering threads are passed.The holes are arranged near themriphery of each disk and as the disksare rotated the several elements which pass through each disk aretwisted to form a cable. In the specific embodiment of the method whichhas been chosen for illustration, four equally spaced holes are providedand elastic filaments are threaded through two of these holes. In thepreferred method the elastic filaments are passed through diametricallyopposite holes. Through the intermediate holes in each disk are passedthe covering threads. In the embodiment of the invention shown hereintwo covering threads are passed through each of the remaining holes sothat each cable is composed of two elastic filaments and four coveringthreads. The purpose of providing a number of covering threadsin excessof the elastic filaments is to assure that the elastic core will becompletely covered by the textile elements.

The rotation of the disks forms a series of successive sheds at eachquarter turn of the several disks and through the shed is passed a pickthread, usually a light cotton thread, by a suitable shuttle orpick-laying device (not shown) so that in the completed fabri the pickthread passes through the several cables and is firmly gripped by theelastic core and the outer wrapping layers.

In making elastic fabric by the present method the two elastic filamentsare maintained under a considerable tension during the operation, withthe result that these two filaments or threads twist together to form a.central cable or core and the outer textile elements are wrapped aroundthe elastic core. When the elastic filaments are located 180 apart on'the disks these filaments are always on opposite, sides of the shed sothat each lay of the pick thread passes between the two twisted elasticfilaments in the center of the fabric.

The direction in which the thread are twisted depends upon the manner inwhich they are threaded through the disks and thedirection of rotationof the disks. Thus, as shown in Fig. 2,

the several strands on the upper three disks pass through the disks inone direction, while the strands in the lower three disks pass throughthe disks in the reverse direction, giving the right and left handtwists depicted at the left of Fig. 2.

As the elastic filaments are under a substantial tension they will twisttightly together and grip the pick thread. They will also grip eachother .and as the elastic threads still retain a substantial tensionwhen the fabric is relaxed, these conditions will remain in the finishedfabric.

It will be understood that the provision of two I covering threads foreach hole in the four-holed disk is optional, and that one thread ormore than two threads may be used.

- In Figs-1 and 2 the several disks are designated as 2, the outer edgesof the disks being provided with gear teeth which engage upper and lowerpinions 3 and 4, one of which is driven. These pinions are usuallyelongated sothat any number of disks may be mounted 'therebetween andaround the pinions are located loose collars I which fit between thedisks and maintain them in proper spaced relation. vSet collars 8 holdthe disk assembly together.

The four holes in the disks are designated as 2a, 2b, 2c and 2d, andthrough the opposite holes 2b and 2d the elastic filaments b and d arepassed.

. Through the two holes Iaand 2c the covering threads a and a" and c and0" respectively, are

passed.

- On the left or far side of the disks all of the strands converge .tothe twisting point X where they are twisted together to form the cable,but as noted above, due to the substantial tension which is maintainedin the elastic filaments b and (1, these filaments will twist togetherto form the central cable while the textile threads a a" c and 0" willmerely wrap about the elastic cable. At or near the twisting point apick or weft thread e is passed through the shed as it is formed, theshuttle preferably making a pass through each successive shed as it isformed by 90 of revolution of the disks. As the pick thread is passedthrough the center of the shed, and as there is always one elasticfilament above and one below the shed, the pick thread will always liebetween the turns of the elastic core and be the elastic cable. It isnot necessary that a pick thread pass through each shed as it is formedand it will also be understood that a double or single pick thread maybe employed.

t will be further noted that when the textile strands are employedinduplicate, the pick thread will always lie between the two sets ofstrands. This condition is illustrated in Fig. 5.

It is desirable to pass a beater (not shown) through each successiveshed so as to line up the twists across the fabric. A beater of anydesign may be employed, but for the best results it should be broughtthrough the shed against the convolutions directly. This is preferableto using an ordinary comb or reed which would bear against the pickthread rather than against the twisted elements of the cable.

From the point X the completed fabric passes through a gathering guide 8and thence to any suitable drawing or wind-up mechanism. In making anelastic fabric it is desirable to advance the fabric at a somewhataccelerated speed with respect to the speed of rotation of the diskswhich causes the outer covering elements to form as long spaced spiralsas indicated at the left of acemes Fig. 1. This is to provide for thepartial retraction of the elastic core when the fabric is released,whereupon the turns or convolutions of the covering move together asshown in Fig. 3.

In Fig. 3 a piece of complete webbing of six cables is shown in itsnormal or relaxed condition, this view showing a construction in whichthe cable twists are alternated. To the right of this view the severalelements of the cable have been untwisted to show the construction.

In the edge view in Fig. 4 it will be noted that the pick thread e onthe selvage encloses the two textile elements or threads.

In a fabric made in accordance with the drawing the elastic filamentsare bare when they enter the disks. If a further covering for theelastic filaments were desirable, each of these filaments could beindividually wrapped before it enters the rotating disks. It is alsopossible, without departing from the principles of the invention toincorporate one or a group of cables made up in accordance with theinvention in the body of a woven fabric.

The rotation of the disks will create a twist in the individual cableson both sides of the disk and in a loom for the manufacture of theimproved fabric, provision may be made to remove the twist from theseveral cables on the incoming side of the disks or the rotation of thedisks may be reversed periodically.

The above are merely examples of the way in which the invention may bemodified and adapted for commercial practices by those skilled in thisart, for the production of a variety of fabrics or patterns, withoutdeparting from the principles of the invention as herein described andclaimed.

What is claimed is:

1. In the art of making an elastic fabric, the steps of twistingtogether a plurality of elastic threads while undentension to form acentral cable, and simultaneously wrapping a series of textile threadsabout the central cable, and passing a pick thread through the cable inadvance of the twisting point.

2. In the art of making an elastic fabric, the steps of twistingtogether a plurality of elastic threads while under tension to form acable, wrapping a textile covering about the cable, and passing a pickthread between the elastic threads in advance of the twisting point.

8. In the art of making an elastic fabric. the steps of passing twoelastic threads and threads of a covering material through holes in arotary disk, maintaining the elastic threads under tension, rotating thedisk to twist the elastic threads to form a central cable and to wrapthe covering threads about the cable, said operation forming successivesheds between the several threads, and passing a pick thread throughsuccessive sheds.

-i=. In the art of making an elastic fabric, the steps of passing twoelastic threads and threads of a covering material through holes inarotary disk, maintaining the elastic threads under tension, rotatingthe disk to twist the elastic threads to form a central cable and towrap the covering threads about the cable, said operation formingsuccessive sheds between the several threads. and

passing a pick thread through successive sheds and between the elasticthreads.

sion, rotating the disk to twist the elastic threads together to form acable and to wrap the covering threads about the cable, the rotation ofthe disk creating successive sheds between the related to theprogression of the threads as to form spaced spirals in the coveringthreads which will close together when the tension on the fabric isreleased.

6. In the art of making an elastic fabric, the steps of forming aplurality of parallel cables from groups of warp threads by twisting theseveral groups of threads together, each group of threads containing twoelastic threads which are maintained under tension during the twistingoperation. and passing a pick thread through the several cables inadvance of the twisting point.

'7. In the art of making an elastic fabric, the steps of forming aplurality of parallel cables from groups of warp threads by twisting theseveral groups of threads together, each group of threads containing twoelastic threads which are maintained under tension during the twistingoperation, and passing a pick thread through the several cables andbetween the elastic threads in advance of the twisting point.

8. In the art of making an elastic fabric, the steps of forming aplurality of parallel cables from groups of warp threads by twisting theseveral groups of threads together, each group of threads containing aplurality of covering threads and two elastic threads which aremaintained and between the elastic threads in advance of the twistingpoint.

10. A process in accordance with claim 1 in which a plurality ofparallel cables are formed by the method set forth and in which the pickthread is passed through all of the cables.

11. A process in accordance with claim 2 in which a plurality ofparallel cables are formed by the method set forth and in which the pickthread is passed through all of the cables.

12. An elastic fabric comprising a plurality of parallel cables. eachcable consisting of an elastic core containing two elastic filamentstwisted together and a plurality of covering threads spirally wrappedabout the core. and a pick thread passing transversely through theseveral cables and between the elastic filaments.

13. A fabric as described in claim 12 in which the elastic core is undertension. 7

5. In the art of making an elastic fabric, the

14. An elastic fabric comprising a plurality of parallel cables, eachcable consisting of an elastic core containing two elastic filamentstwisted together and a plurality of textile threads spirally wrappedaround the core, and a pick thread passing transversely through thecenters of the sev-' eral cables and between the several textile threadsand the elastic filaments.

15. A fabric in accordance with claim 14 in which the elastic cores areunder tension.

STERLING W. ALDERFE'R.

